– A de-aeration valve was installed in the oil passage of the front engine cover starting with engine serial number 201681 through 375549.

– The de-aeration valve is used to eliminate air from the base engine oil system quickly. If the gerotor oil pump losses its prime, this valve allows the air to get out of the oil system quickly.

– As of engine serial number 375549, the complete front cover was redesigned to keep the oil pump primed during initial start-up and the de-aeration valve was eliminated.